i2c总线测试程序

使用工程i2c-utils下载地址

https://gitcafe.com/21cnbao/i2c-utils

该工程支持的reg_address是8位的，由于需要支持16位的，对i2c-util.c做了些修改。

static int i2c_read_reg(char *dev, unsigned char *buf, unsigned slave_address, unsigned reg_address, int len)

{
        struct i2c_rdwr_ioctl_data work_queue;
//      unsigned char w_val = reg_address;
        unsigned char w_val[2];
        int ret;

...

        if (reg_address >> 8)
        {
                (work_queue.msgs[0]).len = 2;
                w_val[0] = reg_address >> 8;
                w_val[1] = reg_address & 0xff;
                (work_queue.msgs[0]).buf = &w_val[0];
        }
        else
        {
                (work_queue.msgs[0]).len = 1;
                w_val[0] = reg_address & 0xff;
                (work_queue.msgs[0]).buf = &w_val[0];
        }
        (work_queue.msgs[0]).addr = slave_address;
//      (work_queue.msgs[0]).buf = &w_val;


//      if (reg_address >> 8)
//              (work_queue.msgs[1]).len = len + 1;
//      else
                (work_queue.msgs[1]).len = len;
        (work_queue.msgs[1]).flags = I2C_M_RD;
        (work_queue.msgs[1]).addr = slave_address;
        (work_queue.msgs[1]).buf = buf;

  ...
}


static int i2c_write_reg(char *dev, unsigned char *buf, unsigned slave_address, unsigned reg_address, int len)
{
        struct i2c_rdwr_ioctl_data work_queue;
        unsigned char w_val = reg_address;
        unsigned char w_buf[len+2];
        int ret;


        if (reg_address >> 8)
        {
                w_buf[0] = reg_address >> 8;
                w_buf[1] = reg_address & 0xff;
        }
        else
                w_buf[0] = reg_address;


  ...


//      (work_queue.msgs[0]).len = 1 + len;
        (work_queue.msgs[0]).addr = slave_address;
        (work_queue.msgs[0]).buf = w_buf;

        if (reg_address >> 8)
        {
                (work_queue.msgs[0]).len = 2 + len;
                memcpy(w_buf + 2, buf, len);
        }
        else
        {
                (work_queue.msgs[0]).len = 1 + len;
                memcpy(w_buf + 1, buf, len);
        }

...
}


int main(int argc, char **argv)
{
        unsigned int fd;
        unsigned int slave_address, reg_address;
        unsigned r_w;
        unsigned w_val;
        unsigned char rw_val;


        if (argc < 5) {
                printf("Usage:\n%s /dev/i2c-x dev_i2c_addr reg_addr rw[0|1] [write_val]\n", argv[0]);
                return 0;
        }


        fd = open(argv[1], O_RDWR);


        if (!fd) {
                printf("Error on opening the device file %s\n", argv[1]);
                return 0;
        }


        sscanf(argv[2], "%x", &slave_address);
        sscanf(argv[3], "%x", ®_address);
        sscanf(argv[4], "%d", &r_w);


        if (r_w == 0) {
                if (i2c_read_reg(argv[1], &rw_val, slave_address, reg_address, 1))
                        printf("Read %s-%02x reg %04x, read value:%02x\n", argv[1],
                                        slave_address, reg_address, rw_val);
        } else {
                if (argc < 6) {
                        printf("Usage:\n%s /dev/i2c-x dev_i2c_addr reg_addr r|w[0|1] [write_val]\n", argv[0]);
                        return 0;
                }
                sscanf(argv[5], "%x", &w_val);
                if ((w_val & ~0xff) != 0)
                        printf("Error on written value %s, only accept 0~FF\n", argv[5]);


                rw_val = (unsigned char)w_val;
                i2c_write_reg(argv[1], &rw_val, slave_address, reg_address, 1);
        }


        return 0;
}